1. Technical Field
The present invention relates in general to the field of electronics, and in particular to electronic chips that generate extraneous heat during normal operation. More particularly, the present invention relates to a method and system for removing heat from an integrated circuit using a dual impeller push-pull axial fan.
2. Description of the Related Art
In a typical personal computer (PC), the main heat-generating component among the logic circuits is the processor, also referred to as the Central Processing Unit (CPU) or microprocessor (MP). As illustrated in FIG. 1a, a processor 102 is mounted in a socket 104, which is mounted on a (printed) circuit board 106 by mating pins 108 from the processor 102 into the socket 104. As processors continue to grow in performance, so does the heat generated by the processors.
To remove heat from processor 102, a heat sink (HS) 110, having a HS base 112 and a plurality of fins 114, is secured to processor 102 by a strap 116 or other attachment means. Heat is conducted from the processor 102 to the HS base 112 and the fins 114, which dissipate heat by conduction and convection to ambient air surrounding fins 114. To provide thermal conduction between a top surface 120 of processor 102 and the HS base 112, thermal grease 118, typically a thermally conductive silicon or filled hydrocarbon grease doped with fillings such as metals, is used.
A major problem with the heat sink 110 shown in FIG. 1a is that it relies on conduction to the ambient air, which may or may not be moving enough to significantly convey away heat from the fins, depending on movement of air about the heat sink caused by fan(s) in a computer case (not shown) that houses the processor 102. To aid in this air movement, a heat sink fan 122, as shown in FIG. 1b, is often used. Heat sink fan 122 includes fan blades 124, which rotate about a hub 126, causing air to be forced down across fins 114 and against HS base 112.
A major problem with the system shown in FIG. 1b is that heated air (having passed across fins 114) continues to flow past other ICs 128a-b that are mounted on circuit board 106 near processor 102. Thus, while processor 102 may be cooled, it is at the expense of the other ICs 128 that are being additionally heated.